login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A112827 Least value k which is the beginning of a null Goldbach chain of length exactly n.. 0
60, 184, 242, 114, 2314, 1382 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

The first even number of A112826(k/2) consisting of a run of n zeros long.

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

a(1)=60; a(2)=184 because A112825(92) and A112825(93)=0 but A112825(91) and A112825(94) are not equal to 0.

a(3)=242 because A112825(121), A112825(122) and A112825(123)=0 but A112825(120) and A112825(124) are not equal to 0.

MATHEMATICA

f[n_] := Block[{p = 2, q = n/2}, While[ !PrimeQ[p] || !PrimeQ[n - p], p++ ]; While[ !PrimeQ[q] || !PrimeQ[n - q], q-- ]; q - p]; t = Table[0, {10000}]; Do[a = f[2n]; If[a < 10000 && t[[a + 1]] == 0, t[[a + 1]] = 2n], {n, 2, 10^6}]; g = Flatten[ Position[t, 0]];

CROSSREFS

Cf. A020481.

Sequence in context: A001034 A119630 A216480 * A181333 A082529 A126248

Adjacent sequences:  A112824 A112825 A112826 * A112828 A112829 A112830

KEYWORD

more,nonn

AUTHOR

Robert G. Wilson v, Sep 05 2005

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Transforms | Superseeker | Recent | More pages
The OEIS Community | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement .

Last modified October 25 03:21 EDT 2014. Contains 248517 sequences.